Zhang Jiaying, An Haishan, Zhang Xueying, Xu Fangjie, Zhou Boqiang
Forestry and Pomology Research Institute, Shanghai Academy of Agricultural Sciences, Shanghai, China.
Shanghai Key Laboratory of Horticultural Technology, Shanghai Academy of Agricultural Sciences, Shanghai, China.
Front Plant Sci. 2022 Jul 22;13:944269. doi: 10.3389/fpls.2022.944269. eCollection 2022.
Loquat ( Lindl. ) is one of the most economically important evergreen fruit crops in China, while it often suffered the injury of cold stress in winter and earlier spring, and the annual yield loss of loquat fruits caused by cold or freezing stress was immeasurable. However, knowledge about the physiological response and molecular mechanism under cold stress is still limited. To investigate the potential regulation mechanism pre- and post-cold stress in loquat and the changes in physiological indicators, a comparative transcriptome analysis was performed against a cold-resistant cv. "Huoju" and a cold-sensitive cv. "Ninghaibai". The results of physiological indicators related to cold resistance indicated that rachis was most sensitive to cold stress and was considered as the representative organ to directly evaluate cold resistance of loquat based on subordinate function analysis. Here, we compared the transcriptome profiles of rachis pre- and under cold stress in "Huoju" and "Ninghaibai". A total of 4,347 and 3,513 differentially expressed genes (DEGs) were detected in "Ninghaibai" and "Huoju", among which 223 and 166 were newly identified genes, respectively, most of them were functionally enriched in plant hormone signal transduction (Huoju: 142; Ninghaibai: 200), and there were higher plant hormone content and related DEG expression levels in "Huoju" than that of "Ninghaibai". Moreover, a total of 3,309 differentially expressed transcription factors (DETFs) were identified, and some DEGs and DETFs were screened to be subjected to co-expression network analysis based on the gene expression profile data. Some candidate DEGs, including UDP-glycosyltransferase (UGT), glycosyltransferase (GT), sugar phosphate/phosphate translocator (SPT), sugar transport protein (STP), proline-rich receptor-like protein kinase (PERK), and peroxidise (POD), were significantly affected by cold stress, and the expression level of these genes obtained from real-time quantitative RT-PCR was consistent with the pattern of transcriptome profile, which suggested that these genes might play the vital roles in cold resistance of loquat. Our results provide an invaluable resource for the identification of specific genes and TFs and help to clarify gene transcription during the cold stress response of loquat.
枇杷（Eriobotrya japonica (Thunb.) Lindl.）是中国经济价值最重要的常绿果树作物之一，然而它在冬季和早春时常遭受低温胁迫的伤害，低温或冻害胁迫导致的枇杷果实年产量损失难以估量。然而，关于低温胁迫下的生理响应和分子机制的知识仍然有限。为了研究枇杷在低温胁迫前后的潜在调控机制以及生理指标的变化，对耐寒品种“火局 杷”和低温敏感品种“宁海白”进行了比较转录组分析。与抗寒性相关的生理指标结果表明，果轴对低温胁迫最为敏感，基于隶属函数分析，果轴被认为是直接评估枇杷抗寒性的代表性器官。在此，我们比较了“火局 杷”和“宁海白”在低温胁迫前和低温胁迫下果轴的转录组图谱。在“宁海白”和“火局 杷”中分别检测到 4347 个和 3513 个差异表达基因（DEGs），其中分别有 223 个和 166 个是新鉴定的基因，它们中的大多数在植物激素信号转导中功能富集（火局 杷：142 个；宁海白：200 个），并且“火局 杷”中的植物激素含量和相关 DEG 表达水平高于“宁海白”。此外，共鉴定出 3309 个差异表达转录因子（DETFs），并基于基因表达谱数据筛选了一些 DEGs 和 DETFs 进行共表达网络分析。一些候选 DEGs，包括 UDP-糖基转移酶（UGT）、糖基转移酶（GT）、糖磷酸/磷酸转运体（SPT）、糖转运蛋白（STP）、富含脯氨酸的类受体蛋白激酶（PERK）和过氧化物酶（POD），受到低温胁迫的显著影响，并且通过实时定量 RT-PCR 获得的这些基因的表达水平与转录组图谱模式一致，这表明这些基因可能在枇杷的抗寒中发挥重要作用。我们的结果为鉴定特定基因和转录因子提供了宝贵资源，并有助于阐明枇杷在低温胁迫响应过程中的基因转录情况。
